Rotary sheath withdrawal system and method

ABSTRACT

A device for withdrawing a sheath from a shaft includes a housing a flexible timing belt that is a continuous band forming a loop that has an inner surface and an outer surface. The timing belt has a plurality of belt teeth on a surface of the timing belt. The delivery device is by rotation of a barrel that is actuated by an actuator coupled to a barrel having a plurality of teeth such that rotation of the barrel such that the barrel teeth engages the belt teeth to cause movement of the timing belt causing movement of the outer sheath.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.17/241,554, filed Apr. 27, 2021, which is a Divisional of U.S. patentapplication Ser. No. 16/940,533, filed Jul. 28, 2020, now U.S. Pat. No.10,993,825, which is a Divisional of U.S. patent application Ser. No.16/599,461, filed Oct. 11, 2019, now U.S. Pat. No. 10,736,762, which isa Divisional of U.S. patent application Ser. No. 16/134,287, filed Sep.18, 2018, now U.S. Pat. No. 10,449,073, which applications are herebyincorporated by this reference in their entireties.

BACKGROUND OF THE INVENTION Field of the Invention

Embodiments of the present invention relate to a stent delivery device,specifically a single-handed thumbwheel driven delivery handle.

Background

There are a number of medical conditions and procedures in which adevice such as a stent is placed in the body to create or maintain apassage. There are a wide variety of stents used for different purposes,from expandable coronary, vascular and biliary stents, to plastic stentsused to allow the flow of urine between kidney and bladder.

Self-expanding stents, as well as balloon expandable stents, may also beused to treat various issues with the vascular system, including, butnot limited to May-Thurner Syndrome and Deep Vein Thrombosis.

Stents are usually delivered in a compressed condition to the targetsite and then, deployed at that location into an expanded condition tosupport the vessel and help maintain it in an open position. Thedelivery system used to implant or deploy at the stent target site inthe diseased vessel using a delivery system.

Stents are commonly delivered using a catheter delivery system. A commontype of delivery system for delivering a self-expanding stent is calleda pull back delivery system. This type of delivery system utilizes twocatheters or shafts which are concentrically arranged, one aroundanother. The stent is carried axially around the distal end of the innercatheter or shaft. The stent is carried to the delivery site on thedistal end of the delivery device, held in its compressed deliveryposition by the outer shaft or catheter. Once at the desired placementsite, the outer shaft is pulled back, releasing the stent toself-expand.

BRIEF SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a rotary handle stentdelivery system and method that obviates one or more of the problems dueto limitations and disadvantages of the related art.

In accordance with the purpose(s) of this invention, as embodied andbroadly described herein, this invention, in one aspect, relates to adelivery device according to principles described herein including acatheter having three concentric shafts including an inner core, anouter sheath over the inner core and an outer support shaft; a timingbelt having a plurality of belt teeth on a surface of the timing belt; atiming belt link coupled to the outer sheath such that movement of thetiming belt link causes movement of the outer sheath; a barrel havingbarrel teeth corresponding to belt teeth; and a thumbwheel coupled tothe barrel such that rotation of the thumbwheel causes movement of thebarrel such that the barrel teeth engage the belt teeth to causemovement of the timing belt causing movement of the outer sheath.

In another aspect, a system for delivery of an intraluminal stentaccording to principles described herein includes a delivery device witha catheter having three concentric shafts including an inner core havingthe intraluminal stent thereon; an outer sheath over the stent in anunexpanded state on the inner core therein, the outer sheath holding thestent in an unexpanded state, the outer sheath translatable coaxiallyover the inner core and the intraluminal stent; and an outer supportshaft at least partially extending over the inner core and the outersheath; a timing belt having a plurality of belt teeth on a surface ofthe timing belt; a timing belt link coupled to the outer sheath suchthat movement of the timing belt link causes movement of the outersheath to expose the intraluminal stent; a barrel having barrel teethcorresponding to belt teeth; and a thumbwheel coupled to the barrel suchthat rotation of the thumbwheel causes movement of the barrel such thatthe barrel teeth engage the belt teeth to cause movement of the timingbelt causing movement of the outer sheath.

In yet another aspect, a method of delivering an medical device to abody according to principles described herein uses a delivery devicewith a catheter having three concentric shafts including an inner core,an outer sheath over the inner core and an outer support shaft; a timingbelt having a plurality of belt teeth on a surface of the timing belt; atiming belt link coupled to the outer sheath such that movement of thetiming belt link causes movement of the outer sheath; a barrel havingbarrel teeth corresponding to belt teeth; a thumbwheel coupled to thebarrel such that rotation of the thumbwheel causes movement of thebarrel such that the barrel teeth engage the belt teeth to causemovement of the timing belt causing movement of the outer sheath; and amedical device over an outer diameter of the inner core; the methodincludes rotating the thumbwheel in a predetermined direction to causethe timing belt to move in direction associated with the predetermineddirection of thumbwheel rotation to cause the timing belt link to movethe outer sheath in a desired direction; and deploying the medicaldevice from a distal end of the inner core to the body as the outersheath moves in the desired direction.

Additional advantages will be set forth in part in the description whichfollows, and in part will be obvious from the description, or may belearned by practice of the invention. The advantages of the inventionwill be realized and attained by means of the elements and combinationsparticularly pointed out in the appended claims. It is to be understoodthat both the foregoing general description and the following detaileddescription are exemplary and explanatory only and are not restrictiveof the invention, as claimed.

Further embodiments, features, and advantages of the rotary handle stentdelivery system and method, as well as the structure and operation ofthe various embodiments of the rotary handle stent delivery system andmethod, are described in detail below with reference to the accompanyingdrawings.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures, which are incorporated herein and form part ofthe specification, illustrate a rotary handle stent delivery system andmethod. Together with the description, the figures further serve toexplain the principles of the rotary handle stent delivery system andmethod described herein and thereby enable a person skilled in thepertinent art to make and use the rotary handle stent delivery systemand method.

FIGS. 1(a)-(c) show various embodiments of a stent delivery handleaccording to principles described herein.

FIG. 2 illustrates an exemplary catheter configuration according toprinciples described herein.

FIG. 3 illustrates is an exploded view of features of a delivery handleaccording to principles described herein.

FIG. 4 is cross-sectional view of an assembled handle according toprinciples described herein

FIG. 5 is a cross-sectional view illustrating motion of the thumbwheeland the timing belt.

FIGS. 6(a)-(c) are cross-sectional views of the delivery deviceaccording to principles described herein and illustrate motion of thetiming belt link and outer sheath upon movement of the thumbwheel.

FIG. 7 is a top view of the delivery device according to principlesdescribed herein.

FIG. 8 illustrates a perspective view of the delivery device accordingto principles described herein, including the catheter device.

FIG. 9 is a cross-sectional line drawing showing detail of an exemplaryembodiment of the thumbwheel assembly.

FIG. 10 illustrates a portion of a thumbwheel according to principlesdescribed herein.

FIG. 11 illustrates exemplary belt teeth.

FIG. 12 illustrates exemplary belt teeth.

FIG. 13 shows a prototype thumbwheel/barrel assembly with a timing belt.

FIG. 14 illustrates an exemplary barrel having two sets of teeth.

FIG. 15 illustrates a modular thumbwheel assembly according toprinciples described herein.

FIG. 16 illustrates an exemplary timing belt with timing belt teeth.

FIG. 17 illustrates an exemplary timing belt with timing belt teeth.

FIGS. 18(a) and 18(b) illustrates a idler that may be used with theposi-drive belt illustrated in FIG. 17.

FIG. 19 shows a prototype thumbwheel/barrel assembly with a timing belt.

FIG. 20 illustrates an alternative type of posi-drive belt that could beused in the delivery assembly according to principles described herein.

FIG. 21 illustrates an alternative type of posi-drive belt that could beused in the delivery assembly according to principles described herein

FIG. 22 illustrates a handle according to principles described herein.

FIG. 23 shows an exemplary thumbwheel lock for use with the handledescribed herein.

FIG. 24 illustrates an exemplary timing belt link for use with aposi-drive belt.

FIG. 25 illustrates an exemplary embodiment of the first part of thetiming belt link of FIG. 24.

FIG. 26 illustrates an exemplary embodiment of the second part of thetiming belt link of FIG. 24.

FIGS. 27, 28 and 29 are photographs showing the chord structure of anexample posi-drive belt, which may be used in a delivery deviceaccording to principles described herein.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the rotary handlestent delivery system and method with reference to the accompanyingfigures. Various embodiments disclosed herein illustrate a device andassociated method for delivering expandable stents or other medicaldevices to implant or deploy a stent or other medical device to a targetsite in the diseased vessel.

FIGS. 1(a)-(c) show various embodiments of a stent delivery handleaccording to principles described herein. As illustrated, the handle 10includes a housing 14 and a thumbwheel/thumbwheel assembly 18, with atriaxial catheter 22 extending therefrom. The catheter may extendthrough strain relief 26 from the housing 10. The strain relief 26 cantake any form, such as being made of polyolefin or other similarflexible material.

Referring to FIG. 2, the catheter 22 includes three concentric or“coaxial” tubes/shafts (a triaxial design): inner core 42, outer sheath34 and an outer support shaft 38. The outer sheath 34 may be tapered orstepped, as illustrated in FIG. 2, or may not be tapered, depending onthe application. The outer support shaft 38 may be a PEEK(polyaryletheretherketone) tubing extrusion or other similar structure.The outer support shaft 38 can be manufactured from any semi-rigidmaterial. PEEK exhibits good mechanical properties to provide supportfor the smaller diameter of the outer sheath and is flexible. PEEK isalso an off-the-shelf component. A material other than PEEK may be usedto form the outer support sheath, and the invention described herein isnot limited to PEEK for use in the outer support shaft 38. Functionally,the outer support shaft 38 and inner core are fixed in position at theproximal end of the delivery system and the outer sheath translatescoaxially over the inner core and inside the outer support shaft 38. Amedical device such as a self-expanding stent (not shown) is held in areduced delivery configuration for insertion and transport through abody lumen to a predetermined site for deployment. The stent (not shown)is carried axially around the inner core 42 and is held in its reduceddelivery configuration by the outer sheath 34. The inner core 42 may bea braid reinforced tube that extends from the distal end to the proximalend of the device. In some embodiments, the inner core 42 may extendfrom the very distal end to the very proximal end (e.g. all the way fromend to end). The inner diameter of the tube of the inner core 42 issized for tracking over a guidewire and the outer diameter of the tubeof the inner core 42 at the distal end is where the stent (not show)will be crimped between to inner core band markers (50). The outersupport shaft 38 is used to stiffen the delivery device so that the arcof the inner core 42 will not change outside of the body when the outersheath 34 is pulled back to release the stent (not shown) toself-expand. The outer support shaft 38 is connected to the handle 10 atthe proximal end of the device, which stiffens the delivery system andreduces friction at the treatment insertion site so that the inner core42 will not be urged forward as the middle shaft/outer sheath 34 ispulled backward. As illustrated in FIG. 2, the catheter 22 may include adistal tip 46. The inner core 42 may further include at least one innercore marker band 50 such that self-expanding stent is crimped and loadedat the distal end of the catheter and located over the inner corebetween two inner core marker bands 50 (only one is shown in FIG. 2) toprevent axial movement of the stent. The crimped and loadedself-expanding stent is circumferentially constrained by the outersheath 34. The outer sheath 34 may also include an outer sheath markerband 54.

The triaxial design allows for more optimal delivery system stabilityand accurate placement during stent deployment as compared to atraditional 2-coaxial delivery system. The system in introduced into thebody at an access location thorough an introducer sheath with hemostasisvalve. Where the stent delivery system enters the introducer sheath intothe body friction is generated at the hemostasis valve. Therefore,during deployment of a traditional 2-axis system as the outer sheath isbeing retracted, it wants to move relative to the introducer sheath dueto friction, resulting in the inner core pushing out the stent versusretracting the outer sheath. The operator needs to compensate for thisand move the entire delivery catheter while deploying the stent tomaintain consistent placement during deployment. With long high radialforce stents (such as venous stents) this can result in distal/proximalmovement (accordion effect) of the entire delivery system duringdeployment of the stent and can result in inaccurate deployment ormalposition of the stent. The triaxial design mitigates this effect asthe outer support shaft 38 is inserted through the introducer sheath andtherefore the friction between the outer sheath translation andintroducer sheath hemostasis valve is eliminated.

FIG. 3 illustrates an exploded view of features of a delivery handleaccording to principles described herein. The exemplary embodimentillustrated in FIG. 3 includes a two-part housing 114 a and 114 b, wherethe respective two parts 114 a and 114 b may be snap fit together forassembly. The thumbwheel 18 may comprise two wheels 118 a and 118 b, anaxle 58, and a bearing 62. The wheels 118 a and 118 b may include teethon an inner barrel 66 thereof. Although only one inner barrel is shownin FIG. 3 on wheel 118 b, wheel 118 a may also include an inner barrelwith teeth. The teeth on the inner barrel 66 are sized to correspondwith teeth on a timing belt 70. A timing belt link 74 connects the outersheath 34 to the timing belt 70. The housing may include a bushing 78,which may be a separate component or may be integral to the housing 14.The bushing may be formed of PEEK or other suitable material. Theexemplary handle of FIG. 3 further includes at least one idler pulley 82for tensioning and guiding the timing belt. Also shown in FIG. 3 idlerpulley axles 86 corresponding to the idler pulleys 82 of the embodimentof FIG. 3. The exemplary delivery handle of FIG. 3 further includes atensioner assembly 90, the tensioner assembly 90 including a torsionspring 94, a tensioner arm 98, a tensioner pulley 102, a tensioner armaxle 106 and a tensioner pulley axle 112. In the presently describedembodiment, the timing belt has teeth on one side (outer diameter orperiphery) of the belt and the inner diameter (inner surface) is smoothor substantially smooth or flat. The smooth or flat surface of thetiming belt 70 contacts the idler pulleys 82 and the tensioner pulley102.

In the exemplary embodiment of FIG. 3, the outer support shaft 38 isfixed to the handle housing 14, and both the inner core 42 and outersheath 34 are contained within the inner diameter of the outer shaft 38.The inner core 42 will be bonded at the proximal end along with a metal(e.g., stainless steel) shaft 30 to a female luer 116, which is coupledto or clamped into the handle body 14. In an aspect of the presentinvention, the metal shaft 30 may be bonded to the outer diameter of theinner core 42 to provide support/rigidity at the proximal end where theinner core 42 is unsupported in the handle body 10. The support of themetal shaft 30 over the inner core 42 mitigates potentialdeformation/buckling of proximal unsupported inner core 42 during stentdeployment. As the outer sheath 34 is pulled back to release/deploy thestent, the inner core 42 is put into compression, therefore theunsupported proximal end of the inner core could deform. The bondedmetal shaft 30 provides support and column strength to unsupportedproximal inner core 42. The metal shaft 30 may be sized such that isslides over the outer diameter of the inner core 42 and through theinner diameter of the outer sheath 34. The metal shaft 30 does notimpact the inner diameter of the inner core 42, so a guidewire (notshown) can still pass through entire assembly. A material other thanmetal may be used to for the support shaft, and the invention describedherein is not limited to metal for use in the support shaft 30.

The outer sheath 34 is coupled to or bonded to the timing belt link 74to deliver the stent by retracting the outer sheath 34 by movement ofthe thumbwheel, which in turn engages the teeth of the timing belt 70via the inner barrel 66 and the teeth on the inner barrel 66. The metalshaft 30 that is coupled to or bonded to the inner core 42/female luer116 is a guide rail that the outer sheath 34 and timing belt link 74move proximally over during deployment.

FIG. 4 is a cross-sectional view of an assembled handle according toprinciples described herein. The exemplary embodiment illustrated inFIG. 4 shows one part 114 b of the two-part housing, where therespective two parts may be snap fit together for assembly. Otherassembly methods may be used to mate the two parts together such aswelding, bonding, gluing or other method. It is contemplated that eachside of the two part housing is symmetrical and complementary, but suchconfiguration is not required. The parts of the thumbwheel assembly 18may be formed by molding, such as injection molding. The housing 14 maybe unitary.

FIG. 4 illustrates one wheel of the thumbwheel assembly 18 that maycomprise two wheels 118 a and 118 b, an axle 58, and a bearing 62. Thebearing may include a ball bearing with an inner and outer groovedbearing race. The bearing serves to reduce rotational friction betweenthe thumbwheel and the axle and may be eliminated if the frictionalforces are acceptable. An acetal bushing or other method of frictionreduction may be used in place of the bearing 62.

The wheels 118 a and 118 b may include teeth on an inner barrel 66thereof. Although only one inner barrel is shown in FIG. 4 on wheel 118b, wheel 118 a may also include an inner barrel with teeth. The teeth onthe inner barrel 66 are sized to correspond with a timing belt 70. Theinner barrel may be formed by molding, such as injection molding, andthe teeth may be formed as part of the molding or other method such thatthe teeth are integral to the inner barrel 66. In another aspect, theteeth may be separable from the inner barrel 66.

As shown, the timing belt link 74 connects the outer sheath 34 to thetiming belt 70. The exemplary handle of FIG. 4 further includes at leastone idler pulley 82 for tensioning and guiding the timing belt 74. Alsoshown in FIG. 4 idler pulley axles 86 corresponding to the idler pulleys82 of the embodiment of FIG. 4. The exemplary delivery handle of FIG. 4further includes a tensioner assembly 90, the tensioner assembly 90including a torsion spring 94, a tensioner arm 98, a tensioner pulley102, a tensioner arm axle 106 and a tensioner pulley axle 112. In theexemplary embodiment of FIG. 4, the outer support shaft 38 is fixed tothe handle housing 14, and both the inner core 42 and outer sheath 34are contained within the inner diameter of the outer shaft 38. The innercore 42 will be bonded at the proximal end along with a metal (e.g.,stainless steel) shaft 30 to a female luer 116, which is coupled to orclamped into the handle body 14.

FIG. 5 further illustrates motion of the thumbwheel 18, timing belt 70and timing belt link 74 for deployment of a stent according toprinciples described herein. As illustrated in FIG. 5, outer sheath 34is translated proximally over guide tube/inner core 42 by the timingbelt 70 by rotating the thumbwheel in the direction of the arrow. Thetiming belt 70 is driven by an operator via dual thumbwheel assembly 18,which may comprise integrally molded gear teeth, the pitch and shape ofwhich correspond to teeth of the timing belt 70 forsynchronizing/engaging the timing belt and causing movement of thetiming belt to cause movement of the timing belt link, which is coupledto the outer sheath 34 to cause movement thereof for unsheathing(deploying) a stent provided therein. The diameter of the inner barrel66, number of teeth on timing belt 70, and the pitch/frequency of theteeth on the timing belt 70 may each be adjusted/modified to allow forvariable mechanical advantage during stent deployment and variabletranslation ratio. In addition, variable speed delivery may also beachieved by actuating the thumbwheel assembly 18 at the desired speed.

In the embodiment illustrated in FIG. 5, rotation of the portionthumbwheel 18 external to the handle proximally (in the direction of thearrow) causes an upper portion of the portion of the timing beltadjacent the portion of the thumbwheel internal to the handle to movedistally (in the direction of the arrow). The timing belt 70 extendsaround an idler pulley 82 such that a portion of the timing belt 70adjacent the timing belt link 74 move proximally (in the direction ofthe arrow), engaging the timing belt link 74 to move the timing beltlink 74 proximally, which moves the outer sheath 34 coupled theretoproximally, thereby unsheathing the stent for deployment. Movement maybe reversed for re-sheathing of catheter following stent deployment.

FIGS. 6(a)-(c) are cross-sectional views of the delivery deviceaccording to principles described herein and illustrates motion of thetiming belt link 74 and outer sheath 34 upon movement of the thumbwheel18 counterclockwise in the context of FIGS. 6(a)-(c). It should beappreciated that the direction of thumbwheel rotation described hereinis described in the context of the cross-section provide, but that it iscontemplated that the portion of thumbwheel external to the handle 14will be rotated rearward (in a proximal direction). It is alsocontemplated that the configuration of the timing belt 70 may beadjusted (for example, looped over the thumbwheel) to modify thedirection of rotation of the thumbwheel corresponding to the proximalmovement (retraction) of the outer sheath 34.

As shown in FIG. 6(a), in an introducing position, the timing belt linkis at a distal end of the handle housing. As the thumbwheel 18 isactuated in a predetermined direction, e.g. in the context of thecross-section shown, counter-clockwise, the timing belt link/shuttle 74moves proximally. Because the timing belt link/shuttle 74 is coupled tothe outer sheath 34, the outer sheath moves proximally with the timingbelt link/shuttle to expose a stent or other medical device mounted onthe inner core 42 (not shown). FIG. 6(b) illustrates the positioning ofthe timing belt link/shuttle in a partially deployed position (e.g. thestent is partially deployed (not shown)). As the thumbwheel 18 isfurther rotated in a timing belt link/shuttle 74 further translatesproximally to allow for full deployment of the stent or medical devicesfrom the of the inner core 42, as shown in FIG. 6(c). In the embodimenthere described, the thumbwheel 18 is actuated such that the upper side(external portion) of the thumbwheel is rotated proximally to cause thetiming belt link/shuttle 74 to transit proximally. It is appreciatedthat the configuration/path of the timing belt 70 may be configured suchthat a distal rotation of the upper side (external portion) of thethumbwheel 18 may cause the timing belt link/shuttle 74 to transitproximally to cause the outer sheath 34 to retract from the inner core42 to allow deployment of the medical device (not shown).

Although not shown in the figures, the thumbwheel may be a singlethumbwheel with appropriate teeth corresponding to the teeth of thetiming belt. As illustrated in the top view of FIG. 7, a thumbwheelcomprising two wheels allows for a balanced design in which the cathetermay exit the handle at a central portion of the distal end of thehandle. FIG. 7 shows an assembled handle 10 and housing 14, and athumbwheel assembly 18 having a first thumbwheel 118 a and a secondthumbwheel 118 b separated by inner barrel 66. This configurationfacilitates operation of the delivery device by holding the handle fromeither the left or the right side, allowing for comparable operationregardless of whether the operator is left or right handed.

FIG. 8 illustrates a perspective view of the delivery device accordingto principles described herein, including the catheter device. As shownin FIG. 8, the timing belt 70 extends around idler pulleys 82 and thetensioner pulley 102 of tensioner 90. The tensioner pulley 102 iscoupled to the torsion spring 94 via the tensioner arm 98. Tension ismaintained on the timing belt by torsion spring 94 on tensioner arm axle106, which urges the tensioner pulley 102 into contact with the timingbelt 70 via the tensioner arm 98. An example idler pulley 82 isillustrated in FIGS. 18(a) and 18(b).

FIG. 9 is a cross-sectional line drawing showing detail of an exemplaryembodiment of the thumbwheel assembly 18 and the timing belt link 74. Asillustrated in FIG. 9, one part 118 b of a two-part thumbwheel 18 has anouter surface 122 that may be textured for ease of use. The thumbwheelpart 118 b may also include an inner surface or rim 126. An inner barrel66 extends from the thumbwheel part 118 b and has a plurality of barrelteeth 130 thereon. The barrel teeth 130 on the inner barrel 66 are sizedto correspond with a timing belt (not shown). Although not illustrated,the barrel teeth 130 may have a standard periodicity (pitch) or may havea variable periodicity (pitch) such that actuation of the thumbwheelassembly may cause movement of the timing belt (not shown) and thustranslation of outer sheath 34 at a first rate when barrel teeth of afirst periodicity engage the timing belt (not shown) and at a secondrate when barrel teeth of a second periodicity engage the timing belt(not shown). Such variable rate may be imparted by having differentspacing/periodicity/pitch of the teeth on the timing belt instead of orin addition to having different spacing/periodicity/pitch of the barrelteeth 130 on the inner barrel 66. FIG. 9 further illustrates thethumbwheel bearing 62 and the thumbwheel axle 58.

A safety locking feature (not shown) may be incorporated in the handledesign such to mitigate inadvertent actuation of the handle duringtransit and storage. The safety locking feature may be aremoval/disposal or toggle feature that engages the teeth on the innerbarrel to lock it in place and prevent rotation. The safety lockingfeature may also be a feature that engages the timing belt link toprevent its translation.

FIG. 10 illustrates a portion of a thumbwheel according to principlesdescribed herein. The thumbwheel may comprise two wheel parts 120 a and120 b, as shown in at least FIG. 3. As illustrated in FIG. 10, one ofthe wheel parts 120 a may be a body 222 including a portion of thethumbwheel 218 a (e.g. the outer circumference a portion of whichextends through the housing such that a user can rotate the thumbwheelto actuate the device) and a portion of the barrel 266 a (e.g. a portionof which engages the timing belt (not shown) to move the timing belt).The wheel part 120 a may be unitary such that the thumbwheel portion 218a that extends through the housing and the barrel portion 266 a may beunitary (e.g., they can be formed in a single molding process). Theother wheel (not shown) may also include both a portion of thethumbwheel for actuation and a portion of the barrel such that the two“wheels” may be fit together to form the thumbwheel and barrel assembly.In other words, the other wheel may be a mirror image of the wheeldescribed above. In some configurations, the two “wheels” may be thesame, such that only one mold may be used. It is also possible that thethumbwheel assembly is formed as a single unit to include both thebarrel and the thumbwheel portions.

As shown in the exemplary embodiment of FIG. 10, the exemplary wheelpart barrel portion 266 a includes grooves 232 that are substantiallyequally/evenly spaced to engage the pitch of a corresponding timing belt(not shown). The timing belt includes a plurality of substantiallyequally/evenly spaced teeth along a face of the belt to engage thegrooves 232 on the corresponding barrel 266. FIG. 11 illustratesexemplary belt teeth. The belt shown in FIG. 11 is exemplary only, as itonly shows two teeth, but the belt is designed to have teeth alongenough of the belt to sufficiently deploy the stent.

Exemplary belt teeth are shown in FIG. 12. As illustrated in FIG. 12,exemplary belt teeth 471 may have a tapered shape with a flat top, e.g.,trapezoidal cross-section, to allow for engagement with the barrel teeth230 or groove 232. Although a trapezoidal cross section is shown, theteeth are not so limited and may be of any cross section that may engagewith the barrel teeth sufficiently to allow belt movement to be actuatedby barrel rotation. Other possible shapes, without limitation, include;without limitation, include circular, cylindrical, diamond, square,triangular or any variation thereof.

In some cases, the timing belt may be looped over the barrel of thethumbwheel to provide more full engagement of the timing belt with thebarrel. In this embodiment, a longer timing belt would be used suchapproximately 360 degrees of engagement may be achieved between the beltand the barrel. FIG. 13 shows a prototype thumbwheel/barrel assembly 522with a timing belt 570 where the barrel width is sized to allow for thetiming belt 570 shown to be looped around the barrel 566 at least onefull revolution. For example, cylindrical surface of the barrel 566 withthe teeth could be sized to be twice the width of the timing belt 570 toaccommodate the timing belt 570 being looped over the barrel 566 twice.The widened barrel 566 might thus have that the two parts of thethumbwheel 518 a and 518 b be spaced further apart than if the timingbelt only engaged the barrel 566 at a fraction of the circumference ofthe barrel 566. In one aspect, the thumbwheel outer cylindrical edgecould be modified to cause some over the outer edge of each portion ofthe thumbwheel to “overhang” the barrel to allow a more surface area foruser engagement.

In another aspect, the barrel may be substantially cylindrical, suchthat an end of the cylinder has a set of teeth and/or grooves and theother end of the cylinder has a set of teeth and/or grooves. The barrelmay further comprise a core region between the ends having teeth and/orgrooves. The barrel with such teeth may be a unitary piece or may be twoparts that are fitted together. The ends of the substantiallycylindrical barrel are spaced apart sufficient to receive a centralportion of a belt therebetween. A timing belt for use with the barrelthus described has a plurality of protrusions on opposite sides of thebelt, for example, extending perpendicular to a pitch axis of the belt.The protrusions are designed to engage corresponding teeth and/orgrooves on the barrel to transfer torque from the barrel to the belt,which is coupled to the outer sheath as described above, to causedeployment of the stent. The barrel may further comprise a groovetherein for receiving a portion of the belt, such that the barrel itselfmay not be substantially cylindrical.

The barrel assembly may be formed by placing two disks withappropriately spaced teeth on circumferential edge thereof a distanceapart sufficient to allow teeth on each of the disks to engage teeth ofthe timing belt. A cylindrical core may extend between each of thedisks. The cylindrical core and “disks” may actually be a unitary piecethat is substantially cylindrical, such that an end of the cylinder hasa set of teeth and/or grooves and the other end of the cylinder has aset of teeth and/or grooves with a core region therebetween. The teethand/or grooves on the two ends may be substantially aligned.

FIG. 14 illustrates an exemplary barrel 666 having two sets of teeth 681with grooves therebetween. Between the two sets of teeth 681, which arearranged around the circumference of a circular cross section, is asurface 668 spacing the sets of teeth 681 apart from one another. Asillustrated, the surface is smooth, but is not so limited. Moreover,although a surface is illustrated, the surface is not necessary. Theteeth may be spaced apart merely be separating two disks with teethand/or grooves on the periphery an appropriate distance apart, perhapswith both disks mounted on common axle (not shown). As discussed indetail, above, the barrel assembly 666 may be unitary, or may be unitarywith the thumbwheels (not shown in FIG. 14). As illustrated in FIG. 15,the thumbwheel assembly with the barrel 666 may modular such that afirst lateral portion of the barrel 666 a and a first lateral portion ofthe thumbwheel 618 a may be unitary and fit together with anotherunitary piece comprising as second lateral portion of the barrel 666 band a second lateral portion of the thumbwheel 618 b. The lateral partsthumbwheel assembly may also include surfaces 668 a and 668 b that whenfitted together form a surface to allow for spacing of the sets of teethapart from one another.

An exemplary timing belt with timing belt teeth are illustrated in FIG.16. A timing belt for use with the barrel thus described has a pluralityof protrusions on opposite sides of the belt, for example, extendingperpendicular to a pitch axis of the belt. The belt shown in FIG. 16 isexemplary only, as it only shows three sets of teeth, but the belt isdesigned to have teeth along enough of the belt to sufficiently deploythe stent.

Exemplary belt teeth are shown in FIG. 17. As illustrated in FIG. 17,exemplary belt teeth may have a cylindrical shape with a flat top, e.g.,trapezoidal cross-section, to allow for engagement with the barrelteeth. Although a trapezoidal cross section is shown, the teeth are notso limited and may be of any cross section that may engage with thebarrel teeth sufficiently to allow belt movement to be actuated bybarrel rotation. Other possible shapes, without limitation, include;without limitation, rounded, trapezoidal, cylindrical, diamond, square,triangular or any variation thereof.

FIG. 18(a) illustrates an idler 1182 that may be used with theposi-drive belt illustrated in FIG. 17. FIG. 18(b) illustrates across-section of the example idler pulley of FIG. 18(a) with theposi-drive belt.

FIG. 19 shows a prototype thumbwheel/barrel assembly 922 having acylindrical core 968 and thumbwheel portions 918 with a timing belt 970having protrusions 971 on two edges of the timing belt 970, such as asingle core posi-drive belt. A cylindrical core 968 can be seen betweentwo sets of teeth/grooves 981.

FIGS. 20 and 21 illustrate an alternative type of posi-drive belt 1171that could be used in the delivery assembly according to principlesdescribed herein. The illustrated posi-drive belt 1170 is “twin core”such that there is a recess or opening 1177 between each “crossbar” ortooth 1171 of the belt. The thumbwheel assembly and pulleys describedherein may be adapted to engage the openings between the teeth of thebelt to perform the movement described herein without impacting theoverall function of the delivery device.

FIG. 22 is a cross-sectional view of an exemplary handle 1010 accordingto principles described herein in combination with an exemplarythumbwheel lock 1011 and an exemplary timing belt link 1074. FIG. 23shows an exemplary thumbwheel lock 1011 for use with the handle 1010described herein. As shown, the exemplary thumbwheel lock 1011 is alevered lock that can be pinched to disengage a portion of the lock 1011from the barrel teeth 1081. More particularly, the thumbwheel lock 1011includes a plurality of teeth 1015 (which may be integral to or unitarywith the thumbwheel lock or otherwise fixed to the thumbwheel lock 1011)that correspond to barrel teeth or to teeth on the surface of thethumbwheel (not shown). The exemplary thumbwheel lock 1011 includes two“lever” arms 1013 connected by a pivot bar 1016. The pivot bar 1016provides pivot or fulcrum points for each of the lever arms 1013. Oneend of each lever arm 1013 includes teeth 1015 to engage a correspondingstructure on the thumbwheel assembly 1018 of the handle 1010. Thepivot/lever arms 1013 have sufficient spring force to clamp onto thethumbwheel assembly 1018 and be held in place by the engagement of theteeth 1015 of the thumbwheel lock 1011 and the thumbwheel assembly teeth1081. The other ends of each of the lever arms 1013 has a sufficientlength and width to allow them to be grasped and pinched together tocause the teeth 1015 of the thumbwheel lock 1013 to move away from thecorresponding structure on the thumbwheel assembly 1018 (e.g., disengagefrom the thumbwheel assembly barrel teeth 1081) and thus be removed fromthe handle 1010 to allow the thumbwheel assembly 1018 to be actuated orrotated.

FIG. 24 illustrates an exemplary timing belt link 1074 for use with aposi-drive belt 1070. As illustrated, the exemplary timing belt link1074 comprises two parts 1074 a and 1074 b that can be snapped together.Each part may be injection molded or formed by any appropriate process.The first part 1074 a fits over the timing belt teeth 1071 of the timingbelt 1070 and snaps around the outer-sheath 1034, trapping a cylindricalfeature 1035 affixed to or integral to the outer-sheath 1034. Thecylindrical feature 1035 may be integral to the outer sheath 1034 orotherwise affixed to the outer sheath 1034 such that the outer sheath1034 may move with the movement of the cylindrical feature 1035. Thesecond part 1074 b snaps onto the outer sheath 1034 from below to createsupport system around the first part 1074 a to provide rigidity. Thesecond part 1074 b provides the strength necessary to withstanddeployment forces. The intent is of this design is to allow rotation ofthe outer sheath 1034 with respect to the belt 1070. According to anaspect of the present design, there is clearance between the timing beltlink parts 1074 a and 1074 b and the outer sheath 1034 and thecylindrical feature 1035 to allow the outer sheath 1034 to spin freelywithout significant interference from the timing belt link 1074 yetallow linear movement of the timing belt link 1074 to cause movement ofthe outer sheath 1034 for deployment of the stent (not shown). Suchmovement is caused by the “entrapment” of the cylindrical feature 1035by the timing belt link 1074. Thus, the system may remain functionalwhen the distal end of the catheter is fixed and the proximal end(handle) is fully rotated 360° about the axis of the catheter (notshown).

FIG. 25 illustrates an exemplary embodiment of the first part 1074 a ofthe timing belt link 1074 a of FIG. 24. The first part 1074 a includesan upper body portion 1076; extension arms 1084 extending in a commondirection from the upper body portion 1076 and engagement grooves 1096complimentary to the teeth 1071 of the timing belt 1070. As illustrated,each extension arm 1084 extends from a corner 1077 of the upper bodyportion 1076, but this the design is not so limited. Distal ends 1085 ofthe extension arms 1084 may be curved so as to engage around thecylindrical outer sheath 1034, e.g. to provide a rough interference orsnap fit. In the illustrated embodiment, there are four extension arms1084, each extending from a corner 1077 of the upper body portion 1076.The upper body portion 1076 has a long dimension 1087 and a shortdimension 1088, where the long dimension 1087 is parallel to the axialdirection of the outer sheath 1034 when engaged with the outer sheath1034 and the short dimension 1088 is roughly perpendicular to the axialdirection of the outer sheath 1034 when engaged with the outer sheath1034. In the exemplary embodiment shown, the engagement grooves 1096 areformed along the long dimension 1087 such that there are at least twogrooves 1096 between to extension arms 1085 on one of the longdimensions 1087 of the upper body portion 1076. The grooves 1096illustrated are U-shaped, such that when there are two such grooves1096, there is a protrusion 1089 from the upper body 1076 at a locationbetween corners 1077 of the upper body 1076 along the long dimension1087 of the upper body 1076 forming two grooves 1096. While two grooves1096 are illustrated, more grooves can be formed by more protrusionsfrom the upper body such that more than two linearly adjacent belt teethcan be engaged. Also, there may be protrusions extending from both longedges/dimensions of the upper body such that grooves on both sides of aposi-drive belt can be engaged. In the presently illustrated embodiment,a longitudinal cross-section of the upper body 1076 may be U-shaped tofit over the outer sheath 1034.

Although not illustrated, the positioning of the extension arms is notlimited to being at the corners of the upper body. In other words, aslong as the extension arms are sufficient to fit around the outer sheathand grooves to engage the timing belt, the position from which theyextend from the outer body can vary. For example, the extension arms mayextend from a mid-point of the long dimension of the upper body, whilethe protrusions may extend from the corner 1077 or end regions of theupper body. Additional protrusions may extend from upper body to allowfor additional timing belt teeth to be engaged by the upper body. Thetiming belt link 1074 may include only the first part but may furtherinclude a second part to provide additional strength to the assembly,e.g., to withstand deployment forces.

As shown in FIG. 26, an exemplary second part 1074 b of may include alower body portion 1075 having two U-shaped end pieces 1079 having asubstantially circular center cut out 1080 sized to receive thecircumference of the outer sheath 1034. The ends 1083 of each “U” areseparated by a distance less than the outer diameter of the outer sheath134 such that the outer sheath 134 can be pushed into the substantiallycircular center cut out 1080 of the “U” shaped end 1079. The U-shapedends 1079 are connected by two upper side rails 1089 extending betweenupper parts of each of the “U”s 1079 to connect the two end pieces 1079.

The outer sheath 1034 can thus be coupled to the drive belt 1070 by thefirst part 1074 a of the timing link 1074 extending over an upperportion of the outer sheath 1034 with the extension arm ends 1085extending under a lower portion of the outer sheath 1034. The secondpart 1074 b of the timing belt link 1074 is located over the extensionarms 1084 of the first part and snap fit around the outer sheath 1034 byinserting the outer sheath 1034 into the substantially circular centercut outs 1080 of the U-shaped ends 1079 of the second part 1074 b. Theouter sheath 1034 may further include a cylindrical body 1035 sized tobe between the extension arms 1085 of the upper body 1076 when the upperbody 1076 is on the outer sheath 1034. For example, the cylindrical body1035 may be permanently fixed to the outer sheath 1034 and thus beengaged by the timing belt link 1074 to hold the timing belt link 1074in appropriate position with respect to the outer sheath 1034.

FIGS. 27, 28 and 29 are photographs showing the chord structure of anexample posi-drive belt, which may be used in a delivery deviceaccording to principles described herein.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

While various embodiments of the present invention have been describedabove, it should be understood that they have been presented by way ofexample only, and not limitation. It will be apparent to persons skilledin the relevant art that various changes in form and detail can be madetherein without departing from the spirit and scope of the presentinvention. Thus, the breadth and scope of the present invention shouldnot be limited by any of the above-described exemplary embodiments butshould be defined only in accordance with the following claims and theirequivalents.

What is claimed is:
 1. A device for withdrawing a sheath from a supportshaft, the device comprising: a housing; a flexible timing belt, whereinthe flexible timing belt is a continuous band forming a loop having aninner surface and an outer surface and having a first plurality of beltteeth and a second plurality of belt teeth extending from the flexibletiming belt; a timing belt link coupled to the sheath such that movementof the timing belt link causes movement of the sheath; a barrel within ahandle, the barrel rotatably coupled to the housing and having barrelteeth corresponding to at least one of the first plurality of belt teethand the second plurality of belt teeth and an actuator operationallycoupled to the barrel to impart rotational motion to the barrel suchthat rotation of the barrel causes movement of the barrel such that thebarrel teeth engage at least one of the first plurality of belt teethand the second plurality of belt teeth to cause movement of the timingbelt causing movement of the sheath via the timing belt link.
 2. Thedevice of claim 1, wherein a portion of the actuator is external to thehousing, wherein the barrel is internal to the housing and the flexibletiming belt is internal to the housing.
 3. The device of claim 1,wherein the first plurality of belt teeth protrudes in a first directionfrom the timing belt and the second plurality of belt teeth protrudes ina second direction from the timing belt.
 4. The device of claim 3,wherein the first direction is different from the second direction. 5.The device of claim 3, wherein the first direction and the seconddirection are parallel.
 6. The delivery device of claim 1, furthercomprising at least one pulley, the flexible timing belt extendingaround the pulley such that the direction of rotation of the barrelimparts a desired direction of translation of the sheath.
 7. Thedelivery device of claim 1, further comprising a belt tensionercomprising a torsion spring, a tensioner arm, a tensioner pulley.
 8. Thedelivery device of claim 7, the belt tensioner further comprising atensioner arm axle and tensioner pulley axle.
 9. The delivery device ofclaim 1, wherein the actuator comprises a thumbwheel.
 10. The deliverydevice of claim 9, wherein the thumbwheel comprises at least twogrooves, and further comprising a thumbwheel lock comprising at leasttwo pivot arms, at least one of the pivot arms including a firstengagement tooth corresponding to at least one of the first groove andthe second groove, the pivot arms having a spring force with respect toone another such that adjacent ends of the pivot arms are biased towardone another.
 11. The delivery device of claim 1, wherein the thumbwheelcomprises a circumferential outer surface having a texture.
 12. Thedelivery device of claim 1, wherein the housing is a handle.
 13. Thedelivery device of claim 1, wherein the outer surface of the flexibletiming belt is adjacent the barrel such that an axis of rotation of thebarrel is external to an area defined by the continuous band.
 14. Thedelivery device of claim 1, wherein the first plurality of belt teethand the second plurality of belt teeth extend from the flexible timingbelt from edges other than the inner surface and the outer surface. 15.The delivery device of claim 1, wherein the actuator is moveable in aforward direction and a reverse direction to cause the barrel to rotatesuch that the sheath translates in first direction when the actuator ismoved in the forward direction and the outer sheath translates in asecond direction when the actuator is rotated in the reverse direction.